Dr Paul Leyland

Forum Replies Created

Viewing 20 posts - 41 through 60 (of 707 total)
  • Author
    Posts
  • in reply to: FITS and FIT files suffix #621444
    Dr Paul Leyland
    Participant

    Ah, the beauty of standards!

    It is very important, IMAO, to have a standard. So important that everyone should have one of their own.

    in reply to: FITS and FIT files suffix #621378
    Dr Paul Leyland
    Participant

    Are the files roughly the same size? The raw files you get from the camera are probably 16-bit integer (BITPIX=16). After calibration they may be floating point (BITPIX=-32) and it may be that Vphot can’t cope with that. The FP files will be twice the size of the integer ones. If Vphot can’t cope with FP that is a bit poor but there may be an option in ASTAP to save as ints.

    I hit exactly that problem with Astrometrica. To solve it I wrote a Perl script to convert from floating point back to 16-bit unsigned integers. Not entirely trivial because a FP number can be negative and the range can be greater than supported in 16 bits, so off-setting and scaling was required.

    in reply to: Astrofest 2024 #621365
    Dr Paul Leyland
    Participant

    David: I am supposed to know what “oscillator strength” means in the context of time dependent quantum mechanics but my memory has rotted in the last 40 years or so and can no longer describe it particularly coherently. Time I ran a refresh cycle on my RAM.

    Mark me as recently mystified.

    Beside which, I will not be Astrofesting this year.

    in reply to: FITS and FIT files suffix #621361
    Dr Paul Leyland
    Participant

    The FITS standard defines a format for metadata headers and mandates some of them.

    Within reason, you can put pretty much anything in there. Whether a particular FITS-reading program interprets them in an intended manner is an entirely different matter.

    For instance, whether either, neither, or both of “EXPOSURE” or “EXPTIME” is present depends on the writing program. My code to read FITS files has to be able to handle both and to work out what to do if their values differ.

    in reply to: BAA song #621334
    Dr Paul Leyland
    Participant

    Everyone else would need ear protection if I were to join in.

    Only dogs like my singing; they howl along with me.

    in reply to: Deep Sky Webinar #621326
    Dr Paul Leyland
    Participant

    Grant, quick question: why do you want a monochrome camera on this kit?

    I can answer why I might find one attractive: I like doing photometry in standard wavebands and also like capturing every possible photon for faint object detection and/or astrometry. I am not very interested in taking pretty picture.

    Paul

    in reply to: Does anyone need iTelescope points for a project? #621306
    Dr Paul Leyland
    Participant

    I can take a look. I have SR, SI and TR filters available. SR has 90% transmission at H-alpha so perhaps that may be the best bet. I also have only 4% of the collecting area of the Hale but, there again, so does WISE.

    No promises of seeing anything by myself, in other words, but perhaps any data I do take can be stacked with those of others.

    in reply to: Does anyone need iTelescope points for a project? #621290
    Dr Paul Leyland
    Participant

    What is the object and what sort of data is required?

    I may be able to help.

    Paul

    in reply to: 2023 – how was it for you? #621231
    Dr Paul Leyland
    Participant

    Now that I am back in La Palma and have access to my observatory I can check the log book.

    It appears that useful observations were made on 43 nights. More were undoubtedly clear, at least in part and some quite probably after I had given up waiting for the clouds to clear earlier in the night.

    Bear in mind that I live in LP for less than half the year. In 2023 only 141 days were spent here and six of those were spent traveling.

    As one might expect the evening I arrived here, 2024-01-11, was clear but I was exhausted after a trip which began at 02:00 that morning. The sky has been cloudy ever since.

    in reply to: BAA Deep-Sky Diaries Nos 1 – 21 #621193
    Dr Paul Leyland
    Participant

    David: please don’t recycle them. I would be happy to collect but I am off to La Palma in a couple of days, returning Easter-ish, so can’t do anything any time soon. If others want them, please give them priority.

    BTW, I have a bunch of BAA Handbook back issues which are free to a good home. They are duplicates of my main collection which is essentially complete back to the 1940s. If anyone may be able to fill gaps, please let me know.

    Paul

    in reply to: Cheap spectrophotometer #621185
    Dr Paul Leyland
    Participant

    Thanks Robin!

    in reply to: True colours of Uranus and Neptune revealed #621165
    Dr Paul Leyland
    Participant

    1993 was my fallow period.

    Marriage tends to do that to people.

    in reply to: 2023 – how was it for you? #621155
    Dr Paul Leyland
    Participant

    Mel: Anything we can do to help?

    Perhaps unlikely, I accept, but please just ask if it is possible.

    in reply to: An Early Quadrantid? #621079
    Dr Paul Leyland
    Participant

    I also thought the same as Bill.

    But soon realised it couldn’t be because of its angle and direction in the sky.

    I may be naive, but I thought that sporadics could come from any direction at any time.

    If that is the case, I don’t see why one shouldn’t masquerade as a shower meteor.

    That said, I am very far from being an expert in these matters and welcome comments from those who are.

    (Yes, I agree with the analysis that it was not a Quadrantid.)

    in reply to: 2023 – how was it for you? #621078
    Dr Paul Leyland
    Participant

    Well, the Earth didn’t move for me, darling, unlike 2021 when some of the tremors went over Richter 3.0.

    I don’t have precise figures to hand right now but impressions are that 2023 wasn’t so much different than the previous couple of years. Cloud was much better than in the UK but calima (hot air bringing dust directly from the Sahara) was as objectionable as ever. In the summer the calima heat was so bad that the camera’s Peltier cooler couldn’t maintain -10C and the mount controller would crash somewhere between 30 seconds and 30 minutes after starting. The latter was eventually kludged around with an old 4″, 12V fan held on with cable ties.

    in reply to: 2 computer issues #621039
    Dr Paul Leyland
    Participant

    For TheSky error with PHD you need to run TheSky one-time-only “As Administrator” so that TheSky’s automation interface is registered with Windows.


    Assuming the above steps fix the problem reboot the computer and carry out a manual “check for Windows updates” from the Windows Settings tool to ensure the Windows Update service is working properly.

    That was it! Discovered it myself a long time ago by trial and error, which is why it was both familiar and not immediately to mind.

    My TCS has had Windows Update switched off in a hard-wired registry setting, so WU never works even when explicitly asked for. That way a working system doesn’t get munged by Microsoft into a non-working one. If it aint broke, don’t fix it. I am not concerned with security vulnerabilities as it is a dedicated system and heavily protected with multiple levels of firewalls. A simple web search will tell you how to follow suit should you wish.

    Paul

    in reply to: 2 computer issues #621024
    Dr Paul Leyland
    Participant

    This looks very familiar but I just can’t put my finger on it right now. I’ll think about it and get back to you.

    in reply to: IAU for amateur astronomers? #621015
    Dr Paul Leyland
    Participant

    I do love a good religious argument, which is why I will jump in feet first.

    Like many, I think taxonomy is very important. There is room, IMO, for the taxonomic term “planet”. Think biology, where “genus” has a rather well defined meaning. Biology also has species and sub-species.

    In my view the adjectives “terrestrial”, “ice-giant”, “super-earth”, “sub-neptune”, “dwarf”, “binary” and “satellite” are all species or sub-species of planet, as are many others.

    Ceres is a dwarf planet. Venus is a terrestrial planet, Ganymede is a dwarf satellite planet, as are Luna and Charon. All are planets.

    Planetologists, as opposed to astrophysicists, appear to agree with this taxonomy.

    Compare Felis catus and Felis sylvestris, each of which live in the UK. Both are Felids.

    • This reply was modified 6 months, 3 weeks ago by Dr Paul Leyland. Reason: Clarification
    • This reply was modified 6 months, 3 weeks ago by Dr Paul Leyland.
    in reply to: Scrapping Honorary Membership ! #620889
    Dr Paul Leyland
    Participant

    Returning to the young members issue: I do not have a solution, far from it, but I am a member of the Cambridge Astronomical Association.

    The CAA has a very thriving and active membership, many of whom are youthful by the standards of other local societies, let alone the BAA. They appeal to primary schoolchildren as well as those a very few decades older.

    One could do much worse than to contact the CAA committee to see how they manage it. Their website is at https://www.cambridgeastronomicalassociation.com/ and I could provide introductions to a few of their people on (off-forum) request.

    in reply to: Scrapping Honorary Membership ! #620875
    Dr Paul Leyland
    Participant

    My personal view: I’m divided. I became an old age perisher this year but I am virtually certain never to be eligible for honorary membership unless the medics make astounding advances in longevity research. I can see, though, that those members with over 40 years continuous membership might be justifiably aggrieved if recognition of their long service was arbitrarily removed.

    On balance, I believe that the best way forward would be to recognize longevity with a physical badge (gold tie pin has been suggested) rather than a financial reward. Honorary membership would continue in name but the subscription model simplified and the Association’s finances improved.

Viewing 20 posts - 41 through 60 (of 707 total)